are there any other concepts such as chromatic harmony concepts, secondary dominants, secondary leading tone chords, augmented 6ths, and borrowed chords that i should wiki? or just anything related to chord changes? such as jazz chord changes like in the song home by michael buble where the chorus goes C Em A C D in the key of G? what is the A doing there? just a thought thanks a lot again

It's a deceptive cadence again. Strictly speaking the following C should be in 1st inversion.

If you listen to that song very carefully, the string section gives the impression of triad over bass.

G/A (Its like I just stepped outside) - A (when everything was going right)

in the song yesterday by the beatles, the chords are g, f#m, B7, em. this looks like the V7 I trick in the key of E harmonic minor. does the f#m serve to strengthen the change to B7? what is this technique/concept called?

It looks to me like it's just a variation of a minor ii(half diminished) V7 i. Really common, check out Autumn Leaves for an example.

hang on i think i understand. lets say im in the key of g and i want to go from g to c. i can instead go g, g7, c and use the g7 in this case to resolve to c without changing key?

yep. That is a classic tonicizattion of IV (you see it all the way back in Bach's music). Once you've tonicized a harmony, you can base a short progression off it, then pull another tonicization to get to V.

If you want to get real prim and proper, label your secondary dominants as V7/? - pronounced "Five-Seven of [whatever]".

I'd do that for a I6/5->V (double sus on the V), but not a ii V. ii and IV are pre-dominants that imply their own harmony.

Think voice leading. Analyzing both as V,the ii would be, then, a V6/5 with the bass moving up by a third to the root of V. Very unorthodox. ii prepares a cadence, but I wouldn't analyze it as part of it.

That all said, if you're just doing a diatonic ii-V-I you can label the whole progression I until it moves to tonicize another harmony (as in the TS's I-V7/IV-IV example).

Bro, we aren't talking CPP voice leading here. We're talking about harmonic motion in music post 1850. Get with the times.

[ii-V] as a grouping can just be reduced to [V] because it's just a distinctive dominant movement the ii is just some extra root motion. You see this in Jazz EVERYWHERE.

IF he sees a [ii-V]/vi in a key, there's no point in him trying to separately analyse where this ii chord is pulled from. Like in the example, F#m in the key of G major. is it...vii? No, that misses the point. It's attached to the V that follows, it's really just a ii-V/vi, or just call it V/vi, because that's what the entire harmonic movement implies functionally.